The Council of Pisa was convoked on March 25, 1409 – as a way to end The Great Schism. Not convened by a Pope, it was NOT recognized as a “lawful” Ecumenical Council. It dealt with the issue of “Conciliarism” - or rather the theory of actual ecclesiastical “Power” laying with The Council and NOT The Pope. Neither Pontiff (there were two), agreed to attend and formed their own “Councils”. Still, many lower Clergy, Theologians and Teachers supported The Pisa theory. This move by both Popes – caused The Pisa Council with “withdraw” it's stated “obedience to them BOTH. As such, they elected a THIRD Pontiff! (Alexander V). Much of the Western Church followed this move. With Alexander's sudden death in 1410, his replacement (John XXIII) – proved equally unmovable and called for the other two “Popes” to step down. Excommunications were handed out (by each, for each). This said state of affairs caused by The Council of Pisa would continue until The Council of Constance of 1417 (and the eventual reinstatement of only 1 Pope).